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High School Living Earth Evidence for Evolution Lessons Name: School: Teacher

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DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B High School Living Earth Evidence for Evolution Lessons Name: School: Teacher: The Unit should take approximately 4 days complete. Read each section and complete the tasks. DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B FIGURE 1: This creosote ring in the Mojave Desert is estimated to be 11 700 years old . This makes it one of the oldest living organisms on Earth . The creosote bush is thought to be the most drought-tolerant plant in North America. It has a variety of adaptations to its desert environment, including its reproductive tendency to clone outward in rings rather than rely solely on seed production. The plant’s leaves are coated in a foul-tasting resin that protects it from water loss through evaporation and from grazing. It only opens its stomata in the morning to pull in carbon dioxide for photosynthesis from the more humid air and closes them as the day’s temperature increases. It also has a root system that consists of both an exceptionally long tap root and a vast network of shallow feeder roots. Creosote bushes exhibit two different shapes to fit different microclimates. In drier areas, the plant has a cone shape in which stems funnel rainwater into the taproot. In wetter areas, the bush has a more rounded shape that provides shade to its shallow feeder roots. PREDICT How do species change over time to adjust to varying conditions? DRIVING QUESTIONS As you move through the unit, gather evidence to help you answer the following questions. In your Evidence Notebook, record what you already know about these topics and any questions you have about them. 1. How can we learn about life on early Earth? 2. How can we trace the lines of descent between species? 3. What are the mechanisms of natural selection, and how do they lead to changes in species over time? UNIT PROJECT © Houghton Mifflin Harcourt Publishing Company • Image Credits: ©Dan Suzio/Science Source Investigating the Evolution of Eyes Go online to download the Unit Project Worksheet to help Eyes are complex organs. Simple eyes let organisms sense light while complex eyes, such plan your project. as those in humans, let organisms see images. Explore how small changes over time can lead to the development of unique features, such as eyes. How can you explain the evolution of eyes? 188 Unit 4 Evidence for Evolution DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B Language Development Use the lessons in this unit to complete the chart and expand your understanding of the science concepts. TERM: fossil Definition Example Similar Term Phrase TERM: geologic timescale Definition Example Similar Term Phrase TERM: tectonic plate Definition Example Similar Term Phrase TERM: evolution Definition Example © Houghton Mifflin Harcourt Publishing Company Similar Term Phrase Unit 4 Evidence for Evolution 189 DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B LANGUAGE DEVELOPMENT TERM: natural selection Definition Example Similar Term Phrase TERM: adaptation Definition Example Similar Term Phrase TERM: artificial selection Definition Example Similar Term Phrase TERM: heritable Definition Example Similar Term Phrase © Houghton Mifflin Harcourt Publishing Company 190 Unit 4 Evidence for Evolution DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B 4.1 Geologic Time Red Rock Canyon State Park is made up of hills with distinctive layers of rock. CAN YOU EXPLAIN IT? Red Rock Canyon State Park in Southern California is known for the dramatic, colorful bands that run through the cliffs. The stripes in the cliffs are different layers of rock that were exposed over time. Within these layers, scientists have discovered more than 100 species of extinct plants and animals that lived from about 12 to about 8 million years ago. Red Rock Canyon has produced one of the most diverse arrays of fossil organisms in Western North America. PREDICT How do you think the rock layers and fossils found in Red Rock Canyon can provide evidence for Earth’s geologic history? What types of information can scientists learn from fossils? © Houghton Mifflin Harcourt Publishing Company • Image Credits: ©Gary C. Tognoni/Shutterstoc Evidence Notebook As you explore this lesson, gather evidence to explain how the history of life on Earth is revealed through rock and fossil records. Lesson 1 Geologic Time 191 DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B EXPLORATION 1 Sedimentary Rock and Fossils Rock is natural, solid, nonliving material that makes up Earth’s crust and much of its interior. Most rock is composed of combinations of one or more minerals. Properties of a particular type of rock—such as color, texture, and mineral composition—are a result of how the rock formed. Through the rock cycle, rocks undergo physical and chemical changes. Other natural cycles are related to the rock cycle. For example, in the water cycle, moving water erodes weathered rock fragments and deposits them in new places where sedimentary rock layers can then form. Water also causes chemical changes as it dissolves rocks such as limestone and marble. Evidence Notebook How do you think the characteristics of rock can be used to determine how it formed and what Earth was like at the time and place where it formed? The Formation of Sedimentary Rock Running water, flowing ice, wind, and gravity move pieces of rock, called sediment, from one place to another over Earth’s surface. Particles of rock settle out of water and air and accumulate as sediment on Earth’s surface. Over time, sediments are buried and compressed. Water moving through pores between the grains of sediment deposits natural cement that glues the grains together. A sedimentary rock forms. FIGURE 1: Grand Staircase Escalante National Monument, Utah INFER Which layers of sedimentary rock at Grand Staircase Escalante National Monument do you think are the oldest? Use evidence to support your claim. Explore Online Sedimentary layers are deposited on top of each other. Unless the layers have been disturbed, the oldest rocks are at the bottom and the youngest are at © Houghton Mifflin Harcourt Publishing Company • Image Credits: ©sumikophoto/Fotolia Hands-On Lab the top. Sediments are also deposited in relatively flat layers. For example, Determining the Relative when a river floods, mud, sand, and gravel are deposited in horizontal layers. Age of Rock Strata Model core Over time these layers are compacted and cemented together into hard rock. sampling and how large-scale forces The top layer makes up the surface of Earth. However, uplift and erosion can change rock strata. expose the layers below the surface. For example, a river can carve into an uplifted sequence of layers and expose them in the canyon or valley walls. 192 Unit 4 Evidence for Evolution DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B Fossil Formation A fossil is the trace or remains of an ancient organism that is preserved in rock Explore Online or sediment. Bones, shells, plant fragments, and bacteria can all be fossilized. Hands-On Lab ANALYZE Use Figure 2 to order the steps involved in the process Explore the Water and Rock of fossilization. Cycles Plan and conduct an investigation to explain a process a. Erosion reveals the layer of rock in which the animal was buried. that involves the water cycle and b. An organism dies and begins to decay. If the organism is not buried rock cycle. soon after death, scavengers may feed on the flesh or microbes may break down carbon-rich molecules in the animal. c. With the soft tissues gone, only hard parts like bones, teeth, and shells remain and these remains are buried within a layer of sediment. d. Fossilization of the animal remains occurs over time. FIGURE 2: Bones, teeth, footprints, and other traces of life can be fossilized or preserved. The processes involved in fossil formation take place on the scale of millions of years. Water level rises; sediment buries the Flesh rots away; bones and footprints. bones remain. If left exposed, the bones would be weathered and eroded by wind, running water, and moving ice. Dinosaur collapses Footprints are and dies. left in the mud. Erosion exposes the layers of strata containing the bones and footprints. A sequence of sediments accumulates over the bones; gradually the bones fossilize. This bed contains the dinosaur bones. Uncountable organisms have existed on Earth over time, but very few have been © Houghton Mifflin Harcourt Publishing Company fossilized. Instead, the bodies of most organisms have decomposed, and their footprints and burrows have been washed away. Specific conditions must exist and certain processes must occur for an organism or its traces to become fossilized. Lesson 1 Geologic Time 193 DO NOT EDIT--Changes must be made through “File info” CorrectionKey=CA-B Cause and Effect Probability of Fossilization The chances that an organism dies and becomes a fossil depend on complex interactions. This is especially true when talking about a soft-bodied organism, an organism without an internal or external skeleton, or the soft body parts (such as tissues) of organisms with skeletons. APPLY What makes soft tissue different from hard tissues? Use evidence to support your answer. Preservation of soft body parts can only occur if the organism is protected from scavengers and decomposers upon death. This means that natural processes must rapidly bury an organism for fossilization to occur. A lack of dissolved oxygen in a body of water can protect the organism from decomposition. Burial in a low-energy environment, such as a lagoon, can also protect the organism from being exposed by erosion, allowing for fossilization.
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